Matthias Monroy

Airbus‘ unmanned glider has been flying for 42 days without landing; no aircraft has been in the air without refueling for such a long time. As a flying Internet node, the drone could replace 250 cell towers. But there is interest mainly from the military.

The „Zephyr“ solar glider breaks more records during a test flight. Launched on June 15, the drone has now been in the air for 42 days, far surpassing the mark of 26 days set in 2018. As then, the test is taking place over a U.S. Army compound in Yuma, the Arizona city considered the sunniest in the world. In theory, the unmanned aircraft can fly continuously for months without maintenance.

With the tests, Airbus and the military want to test the durability of the drone, its electric motors  and its satellite communications. The flights involve intelligence, surveillance and reconnaissance units from the military and various combat commands.

One-third of the weight for batteries

The „Zephyr,“ with its skeletal fuselage, is made of lightweight carbon fiber composites. The wings, with a span of 25 meters, are made of solar cells; Airbus therefore describes the flights as CO2-neutral.

The drone flies in the stratosphere, which refers to altitudes above 15 kilometers of thin air. There, aircraft are above atmospheric weather and conventional air traffic.

The „Zephyr“ is considered the first stratospheric drone of its kind and belongs to the class of so-called High-Altitude Pseudo-Satellites (HAPS). Other defense companies such as Thales rely instead on zeppelin-like systems for this purpose.

First flight in international airspace

The current tests are taking place primarily in airspace over the United States, and the route can be tracked via websites such as Flightradar24. According to the report, the autopilot uses its route to describe words like „Hello“ or „Army“ or even symbols like a hand.

In early July, the drone also flew over the Mexican Gulf to Belize and back to Arizona. This was reportedly the first time it had operated in international airspace and over water.

The current flight is with a „Zephyr 8,“ which is slightly larger than the previous version. In total, the system weighs about 75 kilograms, of which about a third is accounted for by the batteries, which are charged during daylight hours to enable overnight flight. The payload is said to be five kilograms, compared with just half that for the „Zephyr 7.“

For military, border troops and „smart cities“

Airbus is promoting the drone for surveillance and reconnaissance purposes by the military, where the drone could accompany convoys or intercept enemy communications. Other uses would be environmental monitoring or integration into „smart cities.“ In a promotional film, Airbus also shows its use for border surveillance, a purpose that the EU border agency Frontex is also currently investigating.

After an eight hours launch and ascent into the stratosphere, the „Zephyr“ is said to be able to navigate to the desired location, which can be thousands of kilometers away. With high-resolution cameras on board, an area of 20 by 30 kilometers can be observed. It is also possible to equip it with radar, lidar and infrared technologies, as well as hyperspectral sensors.

In addition, the „Zephyr“ should be able to be used as a relay to transmit signals between other aircraft and ground stations when they are separated without line of sight. According to Airbus, these „connectivity services“ would be an alternative and complement to terrestrial and satellite-based solutions.

Range of 250 cell towers

Also under discussion is its use as a flying Internet node. The „Zephyr“ could connect remote areas to the Internet or extend the reach of existing networks. The system’s coverage is equivalent to 250 cell towers, says Airbus.

A second flight of a „Zephyr“ is planned for the coming weeks, this time over the Pacific Ocean. The test is primarily military in nature and is intended to investigate the ability to carry a U.S. Army-designed payload over multiple command posts.

Airbus took over development of the „Zephyr“ from the U.K.-based company QinetiQ in 2013. Among the first customers was the U.K. Ministry of Defense, which has since ordered several systems.

Tests of the unmanned solar glider last year (Airbus).